Cartridge feeding mechanism for automatic cannon



CARTRIDGE FEEDING MECHANISM FOR AUTOMATIC CANNON' Filed May 23, 1947 J. MARTIN Sept. 12, 1950 7 Shee ts-Sheet 1 W/WJANES NAFTA! Sept. 12, 1950 J. MARTIN CARTRIDGE FEEDING MECHANISM FOR AUTOMATIC CANNON Filed May 25, 1947 '7 Sheets-Sheet 2 I IZD I I HI MI-HJII- I.

v Q Q Sept. 12, 1950 J. MARTIN 2,522,457

CARTRIDGE FEEDING MECHANISM FOR AUTOMATIC CANNON Filed May 25, 1947 7 Sheets-Sheet 5 .Tv VEWTOR.

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Arron EX J; MARTIN Sept. 12, 1950 2,522,457 CARTRIDGE FEEDING MECHANISM FOR AUTOMATIC CANNON '7 Sheets-Sheet 4 Filed May 23, 1947 Ewan/rm James MART/IV 47TOF/1/EX Sept. 12, 1950 E J. MARTIN 5 CARTRIDGE FEEDING MECHANISM FOR AUTOMATIC CANNON Filed May 23, 1947 7 Sheets-Sheet 5 A TTOHWEX J. MARTIN 2,522,457

CARTRIDGE FEEDING MECHANISM FOR AUTOMATIC CANNON Sept. 12, 1950 '7 Sheets-Sheet 6 Filed May 25, 1947' mN mN JTTd/FWEX I J. MARTIN 2,522,457 CARTRIDGE FEEDING MECHANISM FOR AUTOMATJIIC CANNON Sept. 12, 1950 '7 Sheets-Shet 7 JM/E/VI'OR.

Filed May 25, 1947 Patented Sept. 12, 1950 2 UNITED STATES PATENT]OFFICE 2,522,45i CARTRIDGE FEEDING MECHANISM-FOR i AUTOMATIC CANNON? 1 j James Martin, Higher Denham, near'Uxbridge;

England Application May 23,1947; seri r mua e In Great'Britain Maya- 1946 I I V 12. Claims- (cuss-sea) I This invention relates to the feeding of am:- munition to automatic cannon, machine guns and the like particularly when the ammunition in the form of cartridges is connected-by a series of links to form a belt with the cartridges disposed transversely to the length thereof and'arranged so that the. belt may be fed step by step into position for separating each cartridge from the belt in turn. and? for loading it into the gun as required. a

The object of this invention is to provide a feed mechanism which will be reliable in operation and readily adaptable to different condi tions and positions ofoperation, which will be of low overall height and exert a highaverage pull on the ammunition belt. It is suitable for use in the wings of aeroplanes and other re;- stricted spaces where it is usually necessary with existing types of feed mechanism to provide'a; bul e or excrescence into which part of, the

mechanism projects and which frequently spoils the smooth contour of the wing and detracts from the aerodynamic efficiency thereof. The present invention avoids this.

According to this invention the ammunition formed into a belt by interconnectin links be- I Y tween adjacent cartridges, is fed automatically in unison with the firing movements of the gun by means of rotatable scroll members acting'on the cartridges to feed the belt step by step transversely to the axis of the gun and to separate breech. For this purpose the gun or a moving part thereof actuates a rack embodying a-shock absorbing or spring cushion device. The rack engages a pinion which acts through a trainof gears and a one way drive device-torotate helical scroll members disposed transversely across the axis of the cartridges and which: act to delink each cartridge in turn from the'feed belt and'to move it into position for loading into the breech of the gun.

1mg: is a epart: sectional side elevation-of an ammunition feed box. suitable for mounting in the swing io-f aniaero'plane in association with an automaticcannonFof' the Hispano 20 mm. type.

Figs. 5. andws' are cross-sectional views showing the rearzand front: scrolls, and

i Fig;- 7 is a" longitudinal; section. showing both scro'llsrandillustrating one stage in the feeding of a series of cartridgestogthe feed lips of" the box: for; insertion in? the gun. breech.

Figs; 8,' 9'and110, l 'igs;';l'l,.12- and 13, Figs. 14, 15 and 16;.Figs. 17, 18=andl9,- Figs.- 20, 21- and 22 are similar. views totFigs'. 5, Band '2 showing successive stage's'in thefeedin of cartridges" tothe gun' br'eechf' 1 v a i Figs-'23 .a-ndc2il' are partsectional end. views andaplanishow-ing; details-of a scroll stop device to preventio'verfeeding, and.

Figsi251and 26 a-r'e s'ectionall detail views show ing'lastiroundiizetainingsprings. v r

In the practical application'of'the invention illustrated.:- in: :the drawings and referring more particularlyv to Figs-.=-1 to "4,the feed mechanism may. beconstructed as an independent unit in a The casing is provided'with an intake opening ii onsone side into which the foremost end of the; ammunition? beltisfiinserted and through which the helt'willbe drawn by the feed mech-i anism' At: the other-side isprovided. a discharge opeiiingicsileading to'a chute for the ejection of v the :cbeltf links? and eiztending transversely across the casing-Elsa support for the ammunition" with a gap therein formin a feedimouth'l through In order that the invention maybe more readily understood, a practical application thereof suit; able for use with an automatic cannon (such as the 2!) mm. Hispano cannon) will now he described with reference to the accompanyingdraw ings in which:

whichafeach cartridge is ied: to the feedilip's 8 as it is -separatedzfrom athe beltand from which it i is loaded-into the. gun by the mechanism of ther'g'un -i-t'se1f.- on the-support is mounted a slidableili-nkplatform"9-. which may be utilised tor-controh a satiety stop to prevent overfeeding or: therammunition. to." the; reed 'mouth 1: and

which will be described in detail with reference to Figs. 23 and 24.

The casing I is mounted on the standard magazine carrier of the gun and is located between the fixed abutment I which engages its front wall II and'the magazine catch lever; I2'=whic h engages-: its rear wall I3 and secures iton the. magazine carrier so that the feed mouth I and feed lips 8 are correctly positioned to supporteach cartridge in turn, ready for insertionin the breech of the gun. The magazine carrier. is held stationary whilst the gun is free to move beneath it under the recoil action when the'gun is fired. This relative movement is utilised to actuate the feed mechanism and to feed each cartridge into the breech of the gun, in turn.

' -by a link 49 to the forked end 3! of the rack 3D. A spring 50 acts on the tail of the sear 4i sov as to enable its end 42 to ride over the bent 43 on its return stroke. The end 42 of the sear 4| may be arranged to override the bent 5 43 owing to the arcuate movement of the latter Front and rear scrolls l4 and I5 are arranged transversely across the casing I with extension" shafts I6 and I1 passing through bearings in the dividing wall 4 and their ends are. also supported in bearings I 8 and I9 in the side walls of the casing. The shaft I1 is provided'with a squared end to receive a tool by which it may be rotated by hand to rotate the scrolls I5 for the initial operation of feeding in the*end of the ammunition belt when loading. The scroll shafts I6 and are provided with toothed gears and 2| secured in driving engagement thereon. The two gears 20 and H are'geared together by intermediate idler gears 22 mounted on shafts 23 fixed in the dividing wall 4 (see Figs. 1 and 4). The pitch of these gears is arranged so that the scrolls do not getout of phase and their angular relation to one another is therefore maintained. The gear 20 on the shaft l6 of the front scroll I4 is providedwith a ratchet 24 with which engages a pawl 25 pivotally supported in a bracket 26 secured to the front but if desired the nose 5| on the bent 43 will act to positively disengage the end 42 of the sear 4| from the bent 43 after a predetermined movement of the rack lever 45. This ensures efiective operation of the feed mechanism by a'relatively small portion of the recoilmover'hnt of the gun and also prevents damage'to'the feed mechanism by any'excess of recoil movement. The buffer spring 34 in'the' hollow rack returns the rack to its forward position after each recoil movement of the gun. The recipro cating movement of the rack acts through the one-way driving ratchet 28 to impart astepby v step movement to the'scr'o'lls I4 and I5. It is wall II of the casing and this ensures that the gears'20, 2| and 22 and the scrolls I4 and I5 can only rotate in one direction. The shaft I! of the rear scroll I5 has a toothed pinion 21 mounted freely thereon and carried by this "pinion is a one-way driving ratchet 2B-which engages with corresponding ratchet teethon theface of the gear 2| and is held in engagement therewith bythe spring 29.

-The two scrolls I4 and I5 which are geared together by their gears 20 and 2| and the idler preferred that the actual driving. force shall'be effected by the return movement -of :the rack 30 under the influence of itsspring34as this tends to exert a smooth and resilient force for feeding the ammunition-to the gun.

Located between the two scrolls I4 and I5 and slidably mounted in discharge opening G'is the link ejector platform 9 which slides transversely over the base 60 in guides BI in the housing '62. The link ejector platform 9 is recessed on this underside 63 to accommodate a spring 64 which comprises a fiat strip o'f'spring steel' be'n'tunto a zig-zag form so as to fit in the shallow-space available beneath the link ejector platform '9. This spring 64 tends" to force the link ejector platform 9 toward the intake opening-5 and over the feed mouth "I; The forward endof the link ejector platform is bevelled at 65 on its underside and a pairof upstanding tabs 66 are arranged at one each side of the forward end of the link ejector platform 9 to be engaged by the foremost cartridgeof the incoming belt of ammunition. These tabs '66 are spaced aparta sufficient distance to enablenthe belt links B which connect the cartridges 'A into" belt form to pass 1' between them. In order to enter the feed mouth the strong buffer spring 34 which is located spring 34 to ensure smooth action and prevent buckling of the spring. The rear guide 32is slotted at 36 on its underside to allow'the teeth ofthe rack 30 to project through to engage the teeth' of the pinion 21.

Reciprocating motion is imparted to 'the'rack 30 by the recoil movement of the gun when it is fired. For this purpose the bracket 40 is mounted onthe gun body and slides to and fro with'it, whilst the casing I of the feed mechanism is mounted on the magazine carrier of the "gun A and is held stationary by suitable connections I each'cartridge A must push back the link ejector platform'Q by engaging against its upstanding tabs 66 and afterithe cartridge has entered the feed mouth I the spring 64 urges the link ejector platform 9 over the feed mouth so that its bevelled end 65 engages the cartridge in the feed mouth. The space in the feed mouth above the feed lips 8 is sufficient to accommodate two cartridges, one above the "others :The beve1led end 65 of the link ejectorplatform' 9 engagesthe uppermost cartridgepressing-it down onto'the lower cartridgeon the feed'lips' 8 so'that the latter is held firmly in the'correct position to be fed into the gun breech by the breech block. In this position the link ejector platform 9 will be held back from the position shown in Fig. 4. This is utilised to control a safety st'op'etoprevent a third cartridge being forced into the feed mouth I when thereare already two-cartridges in position. For this purposea stop lever 'Illcis PiVOfiid at be ween the brackets I2 on the dividing wall 4 of the casing I, (see Figs. 23 and 24). The end of the lever 10 has apin: l3. which projects up through an opening. It inthe base 60 of the housing 62 and engagesin. a recess in the underside of the link ejector platform 9. Vlfhen there are already two cartridges in the feed mouth 7 as shown in Fig. 20, the link ejector platform S will be held back by theupper cartridge so that the stop lever lwill be turned about its pivot H and its upper end 1-5 will be moved into the path of the scroll stop 16 on the face of the ratchet wheel 24 afiixedto the gear 20 of the front scroll M. This will prevent. the feeding of further cartridges to the feed: mouth I until the lower cartridge has been'removed from the feed lips 8 and inser-tedjxin. the breech of the gun by the breech block.- The upper cartridge may thenv descend and-the link ejector platform 9 moves back'under the'infiuence of its spring and turns the lever lll'aboutiits pivot H so as to withdraw its end T from the path of the scroll stop It thus enabling the feeding operations to continue. 3f

A further safety device consistsin providing retaining springs in the feed mouth 1 past which each cartridge A must be pressed down'ontothe feed lips 8 by the cartridge aboveit. -These retaining springs may be three in number andare shown as flat blade springs as which engage one. side of the cartridge case ancl'two 'flat blade springs BI and 82 which engage one at each side of the shell end of the cartridge. A guide 83 is also provided on one side of the feed mouth 7! against which the shell portionof the cartridges may engage. This assist's to keep the cartridges in alignment in the centre of the feed mouth I to ensure correct loading of each cartridg-e'into the breech of the gun. Figs. '25 and 26 show how the retaining springs 80; 8i and 82 act to hold up the last cartridge in a belt of ammunition. As there is no following cartridge to press it down past the retaining springs, it will be held up on the springs asshown and cannot be jammed or damaged by the breech block of the gun as might happen if it were allowed to rest loosely on the feed lips 8. These retaining springs 80, 8! and 82 also act to hold thelower cartridge firmly on the feedlips'fl in the correct position and attitude ready forloading into the gun breech by the breech block.

The operation of the ammunition feed mechanism is illustrated in the series of diagrammatic views Figs. 5, 6 and 7 to Figs. 20, 21 and f22 and is as follows: g g The leading end of a belt or ammunition consisting of a series of cartridges Ainterconnected by belt links B is inserted into the inlet opening 5 and the scrolls l4 and I5 are rotated by hand by a suitable armourers tool fitted on the squared end of the scroll shaft H. The foremost cartridge A is engaged by the scrolls I4 and i5 and the belt is drawn into the position shown in Figs. 5, 6 and 7. The next stage is shown in Figs. 8, 9 and 10 in which further rotation of the scrolls l4 and I5 has drawn the leading cartridge A along the inlet 5 and on to the ridge 5a toward the feed mouth I and the cartridge has engaged the tabs 65 and is pressing back the link ejector platform. In Figs. 11, 12 and 13 the leadin cartridge A has pressed back the link ejector platform 9 and is over the entry to the feed mouth I. In Figs. 14, 15 and 16, cam portions Ma and I511 of the scrolls M and 15 have pressed the foremost cartridge A down into the feed mouth I and out of the belt link B thus performing a delinking operation; the-link Bv being supported by the ridge 5a and the end'of the link: ejector platform '9. In Figs'l'l, 1'8. and 19 the foremost cartridge-Ahas: entered fully into the feed mouth 1' and its forward or shell end has been depressed. by the cam I41) on the feed scroll M.

The link 13 is moving onto the; link ejector platform. 9. the'bevelled end of which is bein pressed by its spring 64"against' the cartridge A soas to press it' down into the feed mouth I. In Figs. 20, 21' and 22, the feed mechanism has completed a further'cycle and a second cartridge A-has been fedj'into the feed mouth I and has pressedthe first. cartridge down onto thefeed lips 8 where it is supported in the correctposi tion with its shellend-inclined downwardly ready to be-loaded into thebreechof the gun. I For this purpose, the gun "is cooked by the cocking mechanism which forms part or the normal gun installation and the breech block is held b-ack by its sear: The gun is then ready forfiring and on operating the firing control, the breech block is released and sweeps forward-carrying the lowermost cartridge-A into the breech of the gun. Thebreech is thus closedthe breech block locked andthe cartridge is fired bythe firing pin striking the cap in the base of the cartridge. The

ertia of its par-ts or because the spring 3541s compressed, the lever 18' and scroll stop 16 "will actto'avoid overfeedingand will prevent a third cartridge being fed to thefeed mouth i. if there are already twocartridg'es in position therein.

The retainingsprings 8Q, 8|"arj1d82 will act.v to

retain the last" cartridge of a belt of cartridges in -the upper part of the Efeed mouth 7 so that it vcannotib'e damaged by the breech block or become jammed or'aocidentally fed into the gun breech. I claim: s

In a mechanism for feeding 'elongate car 'tr 'ds s to n a o at ann ha breec r and a recoil mechanism; the combination one.

pair of spacedhelicalscrolls adapted to engage fspaced points adjacent; each end of an elongate a i g sa d scr sib ns mount above, th bree h of t ca non to .f e r i s tr n r' 'versely into a. position in which-they are aligned with the breech, s toothed rack arranged and positioned to be reciprocated by the recoil mechanism of the cannon, gears arranged and positioned between said rack and said scrolls to trans late the reciprocating movement of said rack into rotatory movement of said scrolls, and a downwardly-directed cartridge feed mouth positioned at the delivery end of said scrolls to receive cartridges from said scrolls'and. position them for insertion in the breech of the cannon.

2. A cartridge feeding mechanism as recited in claim 1 .in which each of said scrolls is provided with a cam portion at the delivery endror forcing a cartridge downwardly in-said feed mouth.

3. A cartridge feeding mechanism as recited in claim 1 in which said scrolls are geared together for synchronous movement in phase.

4. Acartridge feeding mechanism as recited in claim 1 in which the feed mouth is provided with resilient means for supporting the leading car tridge in said mouth.

5. In mechanism for feeding ammunition to automatic cannon, a casing having an inlet opening for a series of cartridges formed into a belt by connecting links, a downwardly directed feed mouth for the cartridges and a, discharge outlet for the belt links; two feed scrolls adapted to engage the front and rear ends of each cartridge, a cam portion on each feed scroll to press each cartridge down into the feed mouth, and recoil actuated operating means comprising a slidable rack with a buffer return spring and a one-way ratchet drive to impart a step by step rotary movement to the feed scrolls.

6. In mechanism for feeding ammunition to automatic cannon according to claim 5, a, safety stop to prevent further operation of the feed scrolls when there are already two cartridges in position in the feed mouth.

7. In mechanism for feeding ammunition to automatic cannon according to claim 5, retaining springs for holding back the last cartridge of a, belt of ammunition so that it will be supported in the feed mouth and cannot be damaged or fed to the breech by the mechanism of the gun.

8. In mechanism for feeding ammunition to automatic cannon, a casing having an inlet opening for a, series of cartridges formed into a belt by connecting links, a downwardly directed feed mouth for the cartridges and a, discharge outlet for the belt links; two feed scrolls adapted to engage the front and rear ends of each cartridge, a cam portion on each feed scroll to press each cartridge down into the feed mouth and recoil actuated operating means comprising a slidable rack with a bufier return springand a one-way ratchet drive to impart a step by step rotary movement to the feed scrolls and toothed gearing interconnecting the feed scrolls in constant angular relation and a ratchet and pawl to prevent reverse rotation of the feed scrolls.

9. In mechanism for feeding ammunition to automatic cannon, a, casing having an inlet openin for a series of cartridges formed into a belt by connecting links, a downwardly directed feed mouth for the cartridges and a discharge outlet for the belt links; two feed scrolls adapted to engage the front and rear ends of each cartridge, a cam portion on each feed scroll to press each cartridge down into the feed mouth, a, spring actuated link ejector platform slidable over the feed mouth and adapted to be pressed back by each cartridge entering the feed mouth and recoil actuated operating means comprisin a slidable rack with a buffer return spring and a oneway ratchet drive'to impart a stepby step rotary movement to the feed scrolls.

10. In mechanism for feeding ammunition to automatic cannon according to claim 9 a scroll stop mounted on one of 'the scroll shafts, a lever pivoted to the casing and adapted to be actuated by the slidable link ejector platform to intercept the scroll stop to prevent the feeding of further cartridges to the feed mouth when there is already a predetermined number of cartridges in the feed mouth.

11. In mechanism for feeding ammunition to automatic cannon, a casing having an inlet for a series of cartridges formed into a belt by connecting links, a downwardly directed feed mouth for the cartridges and a discharge outlet for the belt links; two feed scrolls adapted to engage the front and rear ends of each cartridge, a cam portion on each feed scroll to press each cartridge down into the feed mouth, a spring actuated link ejector platform slidable over the feed mouth and adapted to be pressed back by each cartridge entering the feed mouth and toothed gear interconnecting the feed scrolls in constant angular relation and a ratchet and pawl toprevent reverse rotation of the feed scrolls.

12. In mechanism for feeding ammunition to automatic cannon; a casing to be held in stationary relationship to the gun mounting, helical feed scrolls rotatably mounted in bearings in the casing, a toothed pinion freely mounted on the shaft of one feed scroll, a toothed rack gearing with the pinion and slidably mounted in guides in the casing, means for transmitting the recoil movements of the gun to the slidable rack, a one-way driving device between the pinion and the feed scrolls and means for supporting the leading cartridge in position for insertion in the gun breech by the mechanism of the gun.

JAMES MARTIN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,413,694 'Vollmer Apr. 25, 1922 2,047,596 Romberg July 14, 1936 2,397,501 Meyer Apr. 2, 1946 FOREIGN PATENTS Number Country Date 308,574 Germany June 6, 1922 452,606 Germany Nov. 14, 1927 498,946 Germany May .31, 1930 871,833 France Jan. 22, 19 

